Recently, ultrasmall devices such as micromachines are highly noticed. To realize such ultrasmall devices, it requires a conductive fine wire for feeding electricity to an electrical driving mechanism. However, a general metal fine wire has its crystal grain boundary formed by crystallization, it has problems in increase of electric resistance by impurities segregated in the grain boundary, rupture at grain boundary, and increase in surface roughness in the grain boundary. Accordingly, attention has been paid to carbon fine wire as precise conductive fine wire in an ultrasmall device.
On the other hand, fullerene is a general term of carbon allotrope of carbon atoms bonded like a soccer ball or rugby ball, and its synthesis has been reported by many researchers. The fullerene molecule is largely different in shape from the graphite having a flat bonding surface in layer, and it is a great feature that it has a curvature in bonging surface of fullerene molecule. The fullerene can control the strength, rigidity, electrical resistance, optical property, or magnetic property by enclosing the metal compound or organic compound, overlapping in concentric sphere, or introducing a functional group in the surface, and when a fine wire of fullerene linked regularly and at high crystallinity is obtained, it is expected to be useful as nanoconductive material.
Among fullerene derivatives, the molecule having the highest rate of curvature is C60. C60 was discovered in 1985 (H. W. Kroto, J. R. Heath, S. C. O'Brien, R. F. Curl and R. E. Smailey; Nature, 318 (1985) 162-163), and its mass synthesis method was found in 1990 (W. Kratschmer, Lowel D. Lamb, K. Fostiropoulos and D. R. Huffman; Nature, 347 (1990) 354-357). Recently, an acicular substance composed of this C60 is drawing attention, and it is reported that toluene solution of C60 is obtained (for example, S. Ogawa, H. Furusawa, T. Watanabe and H. Yamamoto, “Observation of condensed structure of C60 assembled from solution,” Journal of Physics and Chemistry of Solids, 61 (2000) 1047-1050). In these methods hitherto reported, C60 deposits from toluene solution of C60, and an amorphous acicular substance of about 20 mm is obtained in about 6 months, and the growth speed was far from practical level in order to manufacture one-dimensional substance composed of fullerene, in particular wire material.
In the meantime, an associated body obtained by adding fullerene lean solvent to solution of fullerene monomer was disclosed (Japanese Patent Application Laid-Open No. 10-1306). But this associated body is a granular substance having fullerene monomer associated by van der Waals force, and it was neither crystal nor fine wire.
Another method was reported for obtaining C60 acicular substance by evaporating solution of dissolving C60 in 95 wt. % hexane and 5 wt. % benzene, in a range from room temperature to 80° C. (Y. Tosida, Jpn. J. Appl. Phys. 1992: 31, L505), but the obtained acicular crystal had a very rough surface and it was polycrystalline. Hence, it cannot be used as conductive material.
The present inventors have previously reported fullerene fine wire as a new conductive material by discovering a method of preparing fullerene fine wire by liquid-liquid interface deposition method using fullerene solution (Japanese Patent Application Laid-Open No. 2003-1600 (U.S. patent application Ser. No. 10/125,333)). However, this material has lattice defect of high density (dislocation, lamination defect), and the properties as semiconductor were not so high as expected.
The present invention is devised in the light of the above background, and it is hence an object thereof to solve the problems of the prior art, and present a fine wire having high crystallinity and semiconductor performance in the basis component unit of fullerene derivative, and a method of manufacturing the same easily.